The purification and characterization of human serum alpha 1 antitrypsin, antithrombin III and alpha 1 (T)-glycoprotein will be undertaken. The reaction of normal and abnormal phenotypes of antitrypsin with various proteases will be investigated by various physico-chemical techniques to gain information which can be related to the functioning of the antitrypsin in vivo. The reaction of antithrombin III with thrombin and heparin will be investigated by chemical, ultracentrifugal and light-scattering techniques. The effect of various small ions (e.g., Ca ion) on the inhibition of clotting by the purified antithrombin III will also be investigated in some detail. The surface structure of certain plasma lipoproteins at air/water and fluorocarbon/water interfaces will be investigated as a model system for the role of the plasma lipoproteins in lipid transport. Concurrent determinations of a) the surface tension and its time dependent variation, and b) the solute concentration at the interface by the use of radioactively labelled protein and lipid components will permit measurement of both the kinetics of surface film formation and any deviation of the data from those that would be obtained were the process strictly diffusion controlled. Model control proteins and lipids will also be investigated to assist in the interpretation of the data.